Pregnancy Weight Gain Calculator
Find recommended pregnancy weight gain based on pre-pregnancy BMI. Track whether you're on target for your current week.
Part of our Health Calculators collection.
Pregnancy Weight Gain Calculator
Free online calculator
Use the BMI Calculator if you don't know yours
How much have you gained so far?
Results update automatically as you type
How to Use This Calculator
- 1
Enter pre-pregnancy BMI.
- 2
Enter current week and weight gained so far.
- 3
See recommended total and whether you're on track.
ACOG Weight Gain Guidelines
Underweight (BMI < 18.5): 28–40 lbs total Normal weight (BMI 18.5–24.9): 25–35 lbs total Overweight (BMI 25–29.9): 15–25 lbs total Obese (BMI ≥ 30): 11–20 lbs total Rate: ~1–5 lbs first trimester, then 0.5–1 lb/week.
Example Calculation
Example: BMI 23, week 20, gained 10 lbs
Inputs
prePregnancyBMI: 23currentWeek: 20currentWeightGain: 10
Result
On track ✅ | Recommended: 25–35 lbs total
Normal BMI target 25–35 lbs. At 20 weeks, expect ~10 lbs.
Frequently Asked Questions
What if I'm gaining too fast?
Focus on nutrient-dense foods, reduce empty calories, and incorporate gentle exercise like walking. Don't restrict severely — the baby needs consistent nutrition. Discuss with your OB.
Does pregnancy weight gain affect birth weight?
Yes — insufficient gain increases low birth weight risk; excessive gain increases macrosomia (large baby) risk. Both affect delivery outcomes. Staying in the recommended range optimises outcomes for both mother and baby.